The present invention relates to a technique in which, by using a communication apparatus which is connected to a network, which receives packets transferred through the network to perform different processes in accordance with communication states between a client and a server that transmit and receive packets, and which changes data accumulated within the apparatus, and generates and transmits a new packet to the outside, plural servers are arrayed (coupled as one server), simultaneous transmission of large-volume data to plural users is realized by a system which requires less space and less electric power, and data reproduction in a high-speed response is realized by broadband transmission at the time of reproduction.
The progress of integration of broadcasting and communications increases the needs of large volume of video distribution services, improving a sensory speed, and reduction in server installation cost and power consumption in a data center. A VOD high-speed distribution apparatus and a VOD distribution system for satisfying these needs are required.
As shown in FIG. 28, a conventional video distribution system is a system 2800 which includes a disk array 2801, servers 2802, and a load balancer 2803.
The disk array 2801 is an apparatus obtained by logically integrating plural hard disks into one. Reading and writing are performed using disk access dedicated lines 2805 such as fiber channels or iSCSI.
The servers 2802 are connected to normal communication lines 2806 and the disk access dedicated lines 2805. When receiving a video data distribution request from a client 2804 through the communication line 2806, video data is read from the disk array 2801 through the disk access dedicated line 2805, and the read data is transmitted to the client 2804 through the communication line 2806.
The load balancer 2803 disperses, among plural servers 2802-i (i=1 to n), the video data distribution request received from the client 2804 through a communication line 2807.
As shown in FIG. 27, each piece of video reproducing software 2705 of a client 2702 includes a reproducing unit which generates a video and a reception buffer which temporarily accumulates video data.
When the video reproducing software 2705 instructs to reproduce data, a video data distribution request is transmitted from the client 2702 to a server 2701. When the server 2701 receives the video data distribution request from the client 2702, distribution of video data 2703 is started. The video data 2703 is temporarily accumulated in the reception buffer of the video reproducing software 2705 of the client 2702. If the amount of video data accumulated in the reception buffer exceeds a threshold value for starting reproduction, the reproducing unit of the video reproducing software 2705 reads the video data from the reception buffer, and reproducing of the video is started.
After the video reproducing software 2705 instructs to reproduce data, the server transmits the video data corresponding to the threshold value for starting reproduction in a broad band, and shortens time for the amount of video data accumulated in the reception buffer to exceed the threshold value for starting reproduction, so that the response speed (time from an instruction of reproduction to starting of reproduction) of video reproduction can be shortened. It is possible to realize video reproduction with a high sensory speed.
In the case where the server transmits the video data in a broad band after the instruction of reproduction, the server needs to be provided with a throughput performance 2603 for high-speed reproduction in addition to a throughput performance 2604 for normal distribution, as shown in FIG. 26.